On the structure vs. property relationship for Flax/silk/epoxy hygromorph composites

Abstract

Abstract In this study, available data was used aiming to modeling the hygrotherm behavior and deeply discuss the hygrothermal behavior of Flax/silk/epoxy composites. In the former study, a programmable and reconfigurable hygrothermal morphing composite with multifunctional shape transformation was studied. The authors studied the following configurations (not all was used for all tests): [90]8, [01907], [02906], and[03905] in different relative humidity (RH) contents (9%, 30%, 44%, 75%, 85%, and 100%). In this new approach, a focus in structure vs. property relationship was given aiming to contribute to the original study. Vapor water absorption, hygroscopic expansion, mass diffusion, and mechanical properties were discussed in terms of direction of the fibers, temperature, and humidity content for different composite configurations. The vapor water absorption increased with the transversal reinforcement, and RH more significantly compared to the longitudinal direction. During storage at an specific RH, flax fibers swelled at different ratios larger than the matrix. Besides, we proved that the properties can be managed by a severe control of fibers’ direction, temperature, and humidity in the moisture-responsive composite materials.